Project Summary: There is a compelling need for prospective, properly controlled studies in women with epilepsy (WWE) during pregnancy to improve maternal and child outcomes. The proposed investigations are pertinent to the NINDS Epilepsy Research Benchmarks, address multiple gaps in our knowledge noted by the American Academy of Neurology, and transform care in WWE. This multicenter investigation employs a prospective, observational, parallel-group, cohort design with an established research team. The FDA requires animal testing of individual AEDs to detect risks of fetal exposure for anatomical teratogenesis (i.e., congenital malformation), but not for functional teratogenesis (i.e., cognitive and behavioral deficits). Further, multiple human AED pregnancy registries are investigating malformations, but not cognitive/behavioral outcomes. Determining the effects of fetal AED exposure on development of neuropsychological abilities requires prospective collection of potential confounding factors and testing of children years after exposure. Thus, it is not surprising that such studies are rare, and the risks for most AEDs have not been assessed. The MONEAD investigation provides a unique cohort of exposed and unexposed children who have been followed prospectively starting in early pregnancy with detailed data collection; MONEAD is the first study to assess the effects of quantitated AED-exposure on neurodevelopment during pregnancy and breastfeeding by directly assessing blood levels in mother, cord blood and infant. This is critical because several commonly used AEDs undergo marked clearance changes during pregnancy with marked individual variability in these changes. Such changes could obscure ?dose? relationships reducing sensitivity of detecting adverse effects. MONEAD is also collecting data on the effects of breastfeeding while taking AEDs which includes blood levels in the child and a breastfeeding diary to directly delineate their exposure. This has never been done previously. The collection of AED levels and other pregnancy related factors is complete. In the proposed continuation grant, the children will undergo detailed neuropsychological testing at 2, 3, 4.5, and 6 years-old. The results will provide clear indications of AED risks to the immature brain for the presently most commonly used AEDs, and provide sentinel data on less commonly used AEDs to direct future studies. The Specific Aims are to determine the long-term effects of in utero and infant AED exposure in the children of WWE on: Aim 1: Cognitive outcomes (e.g., verbal abilities and other cognitive domains including novel measures of cerebral lateralization and creativity), Aim 2: Behavioral outcomes (e.g., adaptive and emotional/behavioral functioning, with measures of autistic behavior, attentional problems and hyperactivity), Aim 3: Determine if breastfeeding when taking AEDs adds additional risks. Hypotheses: Children exposed in utero to certain AEDs will exhibit concentration- dependent impairments in cognitive abilities and abnormal behavior. Continued AED exposure through breastfeeding will not add additional neurodevelopmental risk.